1. Field of the Invention
The present invention relates to a sensor array, and in particular a sensor array that measures capacitive coupling to provide an indication of the magnitude and direction of an applied force.
2. Description of the Related Art
Sensor arrays utilising capacitive sensing are well known in the art. Such arrays are particularly useful for generating a surface map of the magnitude and position of forces applied to them. Many current arrays require that the objects that apply a force to the sensor are themselves conductive, and thus cannot sense the presence of objects composed of insulating materials. In addition, a particular problem with conventional designs lies in their susceptibility to interference from stray capacitance. As they rely on transmitter electrodes lying on the opposite side of a compressible material to receiver electrodes, any attempt to introduce grounded elements results in a near total drop in coupling between electrodes. The amount of noise introduced due to stray capacitances can therefore swamp such prior art systems and result in inaccurate measurements.